CN114941062B

CN114941062B - Method and device for vacuum quenching of knitting needle of circular knitting machine

Info

Publication number: CN114941062B
Application number: CN202210577455.4A
Authority: CN
Inventors: 靳皓程; 王炳昌; 王可山; 孙景山; 孙翠香
Original assignee: Yantai Yongchang Precision Knitting Needle Co ltd
Current assignee: Yantai Yongchang Precision Knitting Needle Co ltd
Priority date: 2022-05-25
Filing date: 2022-05-25
Publication date: 2023-03-24
Anticipated expiration: 2042-05-25
Also published as: CN114941062A

Abstract

The application relates to a method and a device for vacuum quenching of knitting needles of circular knitting machines, relating to the technical field of knitting needle processing equipment, comprising a furnace body, wherein the furnace body is provided with a heating cavity for heating workpieces and a cooling cavity for cooling the workpieces, and is characterized in that: the furnace body is equipped with the preheating machine who is used for preheating the work piece and constructs, preheats the mechanism and include the preheating chamber that is used for the subassembly of bleeding that is used for gas to take out from and is used for depositing the work piece, preheats the cavity, heats the cavity and the cooling chamber all is located the furnace body and sets gradually, and the subassembly intercommunication of bleeding preheats cavity and heating cavity, preheats and is equipped with the sealing door and is used for the power spare that the sealing door opened or closed between cavity and the heating cavity. This application has the effect that improves energy utilization.

Description

Method and device for vacuum quenching of knitting needle of circular knitting machine

Technical Field

The application relates to the technical field of knitting needle processing equipment, in particular to a knitting needle vacuum quenching device of a circular knitting machine.

Background

At present, in order to improve the hardness and the wear resistance of a knitting needle, the knitting needle is heated to a phase-change temperature in the knitting needle processing process, the temperature is kept for a certain time, and then the knitting needle is rapidly cooled in water or oil.

The existing vacuum quenching furnace comprises a furnace body, a bottom frame, a heating device, a vacuumizing system and a cooling system, wherein the heating device is connected to the furnace wall of the furnace body; the cooling system includes a direct cooling system leading to the furnace chamber and an indirect cooling system connected to the furnace wall.

In order to solve the above problems, the inventors believe that when the workpiece needs to be continuously quenched, air enters the furnace body in the process of adding the workpiece, the vacuum-pumping system pumps the air away, the heat in the furnace body is dissipated more, and the energy utilization rate is lower.

Disclosure of Invention

In order to improve the energy utilization rate, the application provides a method and a device for vacuum quenching of a knitting needle of a circular knitting machine.

In a first aspect, the application provides a circular knitting machine knitting needle vacuum quenching device, which adopts the following technical scheme:

the utility model provides a big circular knitting machine knitting needle vacuum quenching device, includes the furnace body, and the furnace body is equipped with the heating cavity that is used for heating the work piece and is used for cooling off the cooling cavity of work piece, the furnace body is equipped with the preheating machine who is used for preheating the work piece and constructs, preheats the mechanism and including the preheating cavity that is used for the gas to take out the subassembly of bleeding that separates and is used for depositing the work piece, preheats cavity, heating cavity and cooling cavity and all is located the furnace body and sets gradually, and the subassembly intercommunication of bleeding preheats cavity and heating cavity, preheats the power spare that is equipped with the sealing door and is used for driving the sealing door to open or close between cavity and the heating cavity.

Through adopting above-mentioned technical scheme, when continuously quenching the work piece, during the transport work piece, the air admission preheats the chamber in, starts power spare, and power spare drive sealing door is opened, and the work piece is carried to the heating chamber in, and the air admission heats the chamber simultaneously, and the waste heat in the heating chamber heats the air, and the subassembly of bleeding takes out the air in the heating chamber to preheat the chamber in, and the hot-air preheats the work piece, is convenient for utilize the waste heat, is favorable to improving the utilization ratio of the energy.

Optionally, the air extracting assembly comprises an exhaust pipe and an air extracting pump, the air extracting pump is arranged at the upper end of the exhaust pipe, a vacuum pressure sensor is arranged in the heating chamber, and the vacuum pressure sensor is electrically connected with the air extracting pump.

Through adopting above-mentioned technical scheme, the pressure of vacuum pressure sensor response heating indoor air, when heating indoor air is more, vacuum pressure sensor output signal, aspiration pump received signal starts, and then is favorable to reducing the air of heating intracavity, and then the risk of oxidation when reducing the work piece heating.

Optionally, the outside of preheating the cavity is equipped with deaerator, deaerator including being used for with the white phosphorus of oxygen emergence reaction, being used for depositing the reaction box of white phosphorus and realizing gas exhaust's outlet duct, the one end and the reaction box of outlet duct are linked together, the other end and the preheating cavity of outlet duct are linked together.

Through adopting above-mentioned technical scheme, the air of outlet duct in with preheating the cavity leads to the reaction box in, and oxygen and white phosphorus in the air take place the reaction, and then are favorable to getting rid of oxygen, reduce the risk of work piece oxidation.

Optionally, the lower extreme of preheating the cavity is equipped with the cistern, and the air vent has been seted up to the lower extreme of preheating the cavity, and the air vent is linked together with the cistern, and the one end intercommunication that the blast pipe was kept away from to the reaction box has the pipe of discharging fume, and the one end that the reaction box was kept away from to the pipe of discharging fume is linked together with the cistern.

Through adopting above-mentioned technical scheme, oxygen and white phosphorus take place the reaction and produce a large amount of white cigarettes, and the pipe of discharging fume leads to the cistern with white cigarette in, and white cigarette takes place the reaction with the water in the cistern and generates phosphoric acid, gives off heat, and the air gets into through the air vent and preheats in the cavity, and then is convenient for preheat the work piece, is favorable to improving the utilization ratio of the energy.

Optionally, the upper end of the water reservoir is communicated with a preheating pipe for preheating the workpiece, and the preheating pipe is horizontally arranged along the moving direction of the workpiece.

By adopting the technical scheme, the mixed liquid of the white smoke and the water flows into the preheating pipe, and the workpiece is preheated through the preheating pipe, so that the utilization rate of energy is further improved.

Optionally, a driving mechanism is arranged in the furnace body, the driving mechanism sequentially penetrates through the preheating chamber, the heating chamber and the cooling chamber, the driving mechanism comprises a clamping piece for fixing a workpiece and a driving piece for driving the clamping piece to move linearly, and the clamping piece is fixedly connected to the upper end of the driving piece.

Through adopting above-mentioned technical scheme, the work piece is fixed to the holder, and driving piece drive holder sideslip, and then be convenient for process the work piece.

Optionally, the clamping part comprises a fixing plate and a chuck for clamping the workpiece, the fixing plate is vertically arranged, the chuck is rotatably connected with the fixing plate, and the chuck is arranged in parallel with the fixing plate.

By adopting the technical scheme, the chuck clamps the workpiece, the chuck is rotated, and the chuck drives the workpiece to rotate, so that the workpiece is uniformly heated.

Optionally, the driving part includes support and at least three drive wheel, and the drive wheel rotates with the support to be connected, and the upper end and the fixed plate fixed connection of support, support rotation are connected with the actuating lever, and actuating lever coaxial coupling has drive sprocket, and the drive sprocket meshing has drive chain, and chuck coaxial coupling has driven sprocket, and driven sprocket meshes with drive chain mutually.

Through adopting above-mentioned technical scheme, the support plays the supporting role to the drive wheel, and the drive wheel rotates, drives the actuating lever and rotates, and the electronic drive sprocket of actuating lever rotates, and drive sprocket drives drive chain and rotates, and drive chain drives driven sprocket and rotates, and driven sprocket drives the chuck and rotates, and then the gyro wheel rotates and drives the chuck rotation, is favorable to reducing the power supply, and then is favorable to the energy saving.

In a second aspect, the application provides a vacuum quenching method for a knitting needle of a circular knitting machine, which adopts the following technical scheme:

a circular knitting machine knitting needle vacuum quenching method comprises the circular knitting machine knitting needle vacuum quenching device, and comprises the following steps:

s1: placing a workpiece in a preheating chamber;

s2: removing oxygen in the preheating chamber;

s3: conveying the workpiece into a heating chamber, exhausting gas in the heating chamber into a preheating chamber, and then performing heating treatment;

s4: and cooling the workpiece in the cooling chamber.

By adopting the technical scheme, the workpiece is quenched by adopting the method, so that the energy is saved, the energy utilization rate is improved, and the preparation quality is high.

To sum up, the application comprises the following beneficial technical effects of at least one circular knitting machine knitting needle vacuum quenching device:

1. the exhaust pipe and the air pump are arranged, so that hot air in the heating chamber can be conveniently pumped into the preheating chamber, the heat in the hot air can be conveniently utilized, and the utilization rate of energy is improved;

2. through setting up white phosphorus, the oxygen in white phosphorus and the air takes place the reaction, is favorable to reducing the content of oxygen in the preheating chamber, and then is favorable to reducing the phenomenon that the work piece is oxidized.

Drawings

FIG. 1 is a schematic view of the whole structure of a knitting needle vacuum quenching device of a circular knitting machine.

FIG. 2 is a schematic view showing the structure of a vacuum pressure sensor, a preheating tube and a sealing door in the embodiment of the present application;

FIG. 3 is a schematic structural diagram of a highlighting fan in an embodiment of the application;

FIG. 4 is a schematic view of the structure of a highlighting chuck in an embodiment of the present application;

FIG. 5 is a schematic view showing the structure of the driving chain in the embodiment of the present application.

Description of reference numerals: 1. a furnace body; 4. a heating chamber; 5. a cooling chamber; 11. a feed gate; 12. a sealing door; 3. a preheating mechanism; 31. preheating a chamber; 13. a driving oil cylinder; 32. an exhaust pipe; 33. an air pump; 34. a vacuum pressure sensor; 35. white phosphorus; 36. a reaction box body; 37. an air outlet pipe; 371. an exhaust pump; 38. a smoke exhaust pipe; 381. a fan; 39. a reservoir; 391. a shunt tube; 392. a preheating pipe; 393. a water pump; 2. a drive mechanism; 21. a clamping member; 22. a drive member; 221. a support; 222. a drive wheel; 223. a drive rod; 224. a drive motor; 225. a driving gear; 226. a driven gear; 211. a fixing plate; 212. a chuck; 213. a drive sprocket; 214. a drive chain; 215. a driven sprocket; 216. a rotating shaft.

Detailed Description

The present application is described in further detail below with reference to the accompanying drawings.

The embodiment of the application discloses a circular knitting machine knitting needle vacuum quenching device.

Referring to fig. 1 and 2, a circular knitting machine knitting needle vacuum quenching device, including furnace body 1, actuating mechanism 2, preheat mechanism 3, a heating chamber 4 for heating the work piece, a cooling chamber 5 for cooling the work piece, furnace body 1 is the cuboid, preheat mechanism 3 including preheating chamber 31, preheat chamber 31, heating chamber 4 and cooling chamber 5 all are located furnace body 1 and set gradually, actuating mechanism 2 sliding connection is in furnace body 1, actuating mechanism 2 passes preheating chamber 31, heating chamber 4 and cooling chamber 5 in proper order. The furnace body 1 is opened, the workpiece is placed on the driving mechanism 2, the driving mechanism 2 drives the workpiece to sequentially penetrate through the preheating chamber 31, the heating chamber 4 and the cooling chamber 5, the preheating chamber 31 preheats the workpiece, the heating chamber 4 heats the workpiece, and the cooling chamber 5 cools the workpiece.

Referring to fig. 1 and 2, one end of the furnace body 1 is hinged with a feeding door 11, when the feeding door 11 is closed, the feeding door 11 and the furnace body 1 are arranged in a sealing manner, the furnace body 1 is provided with a sealing door 12, the sealing door 12 is positioned between the preheating chamber 31 and the heating chamber 4, a power part is arranged in the heating chamber 4, the power part comprises a driving oil cylinder 13, a cylinder body of the driving oil cylinder 13 is hinged with the heating chamber 4, and a piston rod of the driving oil cylinder 13 is hinged with the sealing door 12. The feeding door 11 is opened, so that the workpiece can be conveniently placed in the preheating chamber 31, when the workpiece moves to the position of the sealing door 12, the driving oil cylinder 13 is started, the piston rod of the driving oil cylinder 13 contracts to drive the sealing door 12 to be opened, and the workpiece can be conveniently moved into the heating chamber 4 to be heated.

Referring to fig. 1 and 2, the preheating mechanism 3 further includes an air extracting assembly, the air extracting assembly includes an exhaust pipe 32 and an air extracting pump 33, one end of the exhaust pipe 32 is communicated with the heating chamber 4, the exhaust pipe 32 is fixedly connected with the heating chamber 4, the other end of the exhaust pipe 32 is communicated with the preheating chamber 31, and the exhaust pipe 32 is fixedly connected with the preheating chamber 31. The air pump 33 sets up the upper end at blast pipe 32, and the air in the air pump 33 will heat chamber 4 is taken out to preheating chamber 31 in through blast pipe 32, is favorable to reducing the risk of oxidation when the work piece heats, and the waste heat in the heating chamber 4 heats the air, and the air gets into and preheats the work piece in preheating chamber 31, is favorable to improving the utilization ratio of heat energy.

Referring to fig. 1 and 2, a vacuum pressure sensor 34 is disposed in the heating chamber 4, the vacuum pressure sensor 34 is fixedly connected to an upper end of the heating chamber 4, and the vacuum pressure sensor 34 is electrically connected to the suction pump 33. Vacuum pressure sensor 34 induction heating cavity 4 internal pressure, when the heating cavity 4 air is more, vacuum pressure sensor 34 output signal, aspiration pump 33 received signal starts, and then will heat the cavity 4 internal air and take out to preheating in the cavity 31, further reduced the phenomenon of oxygen oxidation work piece in the air, be favorable to improving the work piece quality, steam heats the follow-up work piece of treating processing simultaneously, be favorable to make full use of heat energy, improved the utilization ratio of the energy.

Referring to fig. 2 and 3, the preheating mechanism 3 further includes a deoxidizing device, the deoxidizing device includes a large amount of white phosphorus 35, a reaction box 36 and an air outlet pipe 37, the white phosphorus 35 is placed in the reaction box 36, one end of the air outlet pipe 37 is communicated with the preheating chamber 31, the air outlet pipe 37 is fixedly connected with the preheating chamber 31, the other end of the air outlet pipe 37 is communicated with the reaction box 36, and the air outlet pipe 37 is fixedly connected with the reaction box 36. The air outlet pipe 37 is provided with an air exhaust pump 371 used for air exhaust, the air exhaust pump 371 pumps the air in the preheating chamber 31 into the reaction box 36, the oxygen of the air reacts with the white phosphorus 35 in the reaction box 36, and then the oxygen in the air is favorably removed.

Referring to fig. 2 and 3, a smoke exhaust pipe 38 is fixedly connected to one end of the reaction tank 36 far away from the gas outlet pipe 37, the smoke exhaust pipe 38 is communicated with the reaction tank 36, a fan 381 is arranged in the smoke exhaust pipe 38, a water storage tank 39 is communicated to one end of the smoke exhaust pipe 38 far away from the reaction tank 36, the smoke exhaust pipe 38 is fixedly connected to the upper end of the water storage tank 39, the water storage tank 39 is fixedly connected to the lower end of the preheating chamber 31, and a plurality of vent holes are formed in the lower end of the preheating chamber 31 and communicated with the water storage tank 39.

Referring to fig. 2 and 3, after oxygen in the air reacts with the white phosphorus 35, a large amount of white smoke is generated, the fan 381 is started, the white smoke is conveyed into the water reservoir 39 through the smoke exhaust pipe 38 by the fan 381, the white smoke reacts with water to release heat, and residual hot gas enters the preheating chamber 31 through the vent hole to preheat a workpiece, so that the utilization rate of energy is improved.

Referring to fig. 2 and 3, one end of the water reservoir 39 is communicated with two dividing pipes 391, the dividing pipes 391 are vertically arranged, one end of the dividing pipes 391, which is far away from the water reservoir 39, is communicated with a preheating pipe 392, the preheating pipe 392 is horizontally arranged along the length direction of the preheating chamber 31, the dividing pipes 391 are provided with a water pump 393, liquid in the water reservoir 39 is conveyed into the dividing pipes 391 through the water pump 393, the dividing pipes 391 collect the liquid into the preheating pipe 392, the preheating pipe 392 is cuboid, and one end of the preheating pipe 392, which is far away from the dividing pipes 391, penetrates through the upper end of the preheating chamber 31.

Referring to fig. 2, the water pump 393 conveys liquid in the reservoir 39 to the shunt tubes 391, the shunt tubes 391 convey the liquid to the preheating tubes 392, and the preheating tubes 392 preheat the workpiece, so that the heat energy can be fully utilized, and the utilization rate of energy is further improved.

Referring to fig. 4 and 5, the driving mechanism 2 includes a clamping member 21 and a driving member 22, the driving member 22 includes a bracket 221, four driving wheels 222, two driving rods 223 and a driving motor 224, the driving motor 224 is fixedly connected with the bracket 221, an output shaft of the driving motor 224 is fixedly connected with a driving gear 225, one driving rod 223 is coaxially and fixedly connected with a driven gear 226, the driven gear 226 is meshed with the driving gear 225, two ends of the driving rod 223 are connected with the driving wheels 222, the two driving rods 223 are rotatably connected with two ends of the bracket 221, the furnace body 1 is provided with two sliding rails, and the driving wheels 222 are matched with the sliding rails. The driving motor 224 is started, the output shaft of the driving motor 224 drives the driving gear 225 to rotate, the driving gear 225 drives the driven gear 226 to rotate, the driven gear 226 drives the driving rod 223 to rotate, the driving rod 223 drives the driving wheel 222 to rotate, and the driving wheel 222 moves along the sliding rail direction, so that the driving support 221 is convenient to drive to transversely move.

Referring to fig. 4 and 5, the clamping member 21 includes a fixing plate 211, a chuck 212 and a linkage assembly, the fixing plate 211 is vertically disposed, a lower end of the fixing plate 211 is fixedly connected to the bracket 221, the chuck 212 is disposed in parallel to the fixing plate 211, one end of the chuck 212 is fixedly connected to a rotating shaft 216, and the rotating shaft 216 is rotatably connected to the fixing plate 211. The linkage assembly comprises a driving sprocket 213, a driving chain 214 and a driven sprocket 215, wherein one end of the rotating shaft 216 penetrating through the fixing plate 211 is coaxially and fixedly connected with the driven sprocket 215, the driven sprocket 215 is meshed with the driving chain 214, one end of a driving rod 223 is coaxially and fixedly connected with the driving sprocket 213, and the driving sprocket 213 is meshed with the driving chain 214. When the driving rod 223 rotates, the driving sprocket 213 is driven to rotate, the driving sprocket 213 drives the driving chain 214 to rotate, the driving chain 214 rotates to drive the driven sprocket 215 to rotate, the driven sprocket 215 rotates to drive the rotating shaft 216 to rotate, the rotating shaft 216 drives the chuck 212 to rotate, and the chuck 212 drives the workpiece to rotate. Thereby being beneficial to heating the workpiece uniformly.

The application principle of the knitting needle vacuum quenching device of the circular knitting machine in the embodiment of the application is as follows: while the workpiece is being processed, the user opens the loading door, mounts the workpiece on the chuck 212, and closes the loading door. Starting an air outlet pump, pumping air in the preheating chamber 31 into the reaction box body 36 by the air outlet pump, reacting oxygen in the air with white phosphorus 35 in the reaction box body 36 to generate white mist, starting a fan 381, blowing the white mist into a water reservoir 39 by the fan 381, mixing the white mist with water to form mixed liquid, enabling hot gas to enter the preheating chamber 31 through a through hole, conveying the mixed liquid into a liquid separating pipe by a water pump 393, conveying the liquid in the liquid separating pipe into a preheating pipe 392, preheating the workpiece by the preheating pipe 392, and preheating the workpiece by the hot gas.

The driving motor 224 is started, an output shaft of the driving motor 224 rotates to drive the driving rod 223 to rotate, the driving rod 223 drives the driving wheel 222 to rotate, the driving wheel 222 slides along the sliding groove, the bracket 221 drives the fixing plate 211 to transversely move, the fixing plate 211 drives the chuck 212 to transversely move, and the chuck 212 drives the workpiece to transversely move. When the workpiece moves to the position of the sealing door 12 in a transverse mode, the driving oil cylinder 13 is started, a piston rod of the driving oil cylinder 13 contracts to drive the sealing door 12 to be opened, gas enters the heating chamber 4, waste heat in the heating chamber 4 heats the gas, and when the vacuum pressure sensor 34 senses the pressure of the gas, the air pump 33 is controlled to pump the gas in the heating chamber 4 into the preheating chamber 31.

The embodiment of the application also discloses a vacuum quenching method for the knitting needle of the circular knitting machine, which adopts the following technical scheme:

a vacuum quenching method for a circular knitting machine knitting needle comprises the following steps:

s1: fixing the workpiece on the clamping member 21;

s2: oxygen in the preheating chamber 31 is removed through an oxygen removing device;

s3: opening the sealing door 12, conveying the workpiece into the heating chamber 4 by the driving part 22, exhausting gas in the heating chamber 4 by the air pump 33, and then performing heating treatment;

s4: the workpiece is then conveyed into the cooling chamber 5 for cooling.

The above embodiments are preferred embodiments of the present application, and the protection scope of the present application is not limited by the above embodiments, so: all equivalent changes made according to the structure, shape and principle of the present application shall be covered by the protection scope of the present application.

Claims

1. The utility model provides a big circular knitting machine knitting needle vacuum quenching device, includes furnace body (1), furnace body (1) are equipped with heating chamber (4) that are used for heating the work piece and cooling chamber (5) that are used for cooling the work piece, its characterized in that: the furnace body (1) is equipped with preheating mechanism (3) that is used for preheating the work piece, preheating mechanism (3) is including being used for gaseous pumping the subassembly of bleeding from and preheating chamber (31) that is used for depositing the work piece, preheat chamber (31), heating chamber (4) and cooling chamber (5) all are located furnace body (1) and set gradually, the subassembly intercommunication of bleeding preheats chamber (31) and heating chamber (4), preheat and be equipped with sealing door (12) between chamber (31) and heating chamber (4) and be used for driving the power part that sealing door (12) opened or closed, the outside of preheating chamber (31) is equipped with deaerator, deaerator is including white phosphorus (35) that are used for reacting with oxygen, be used for depositing reaction box (36) of white phosphorus (35) and realize gaseous exhaust outlet duct (37), the one end of outlet duct (37) is linked together with reaction box (36), the other end and the preheating chamber (31) of outlet duct (37) are linked together, the lower extreme of preheating chamber (31) is equipped with cistern (39), preheat the lower extreme of chamber (31) and offered the air vent hole, be linked together with reservoir (39) and reaction box (37), the one end of reaction box (37) is kept away from the vent hole (38), the one end of preheating chamber (39) is linked together, the communicating pipe (38) of preheating is used for discharging fume the reaction of discharge fume, the communicating pipe (39) is kept away from the reaction box (39) is connected with the reaction box (39), the reaction box (39) of preheating the stand-up, the communicating pipe (39), the preheating pipe (392) is horizontally arranged along the moving direction of the workpiece, the air extracting assembly comprises an exhaust pipe (32) and an air extracting pump (33), the air extracting pump (33) is arranged at the upper end of the exhaust pipe (32), a vacuum pressure sensor (34) is arranged in the heating chamber (4), the vacuum pressure sensor (34) is electrically connected with the air extracting pump (33), a driving mechanism (2) is arranged in the furnace body (1), the driving mechanism (2) sequentially penetrates through the preheating chamber (31), the heating chamber (4) and the cooling chamber (5), the driving mechanism (2) comprises a clamping piece (21) used for fixing the workpiece and a driving piece (22) used for driving the clamping piece (21) to linearly move, the clamping piece (21) is fixedly connected to the upper end of the driving piece (22), the clamping piece (21) comprises a fixing plate (211) and a chuck (212) used for clamping the workpiece, the fixing plate (211) is vertically arranged, the chuck (212) is rotatably connected with the fixing plate (211), the chuck (212) is parallel to the fixing plate (211), the driving piece (22) comprises a bracket (221) and at least three driving wheels (222), the driving wheel (221) is rotatably connected with the bracket (223), and the fixing plate (223) is rotatably connected with the fixing plate (221), the driving rod (223) is coaxially connected with a driving chain wheel (213), the driving chain wheel (213) is meshed with a driving chain (214), the chuck (212) is coaxially connected with a driven chain wheel (215), and the driven chain wheel (215) is meshed with the driving chain (214).

2. A vacuum quenching method for knitting needles of circular knitting machines, comprising the vacuum quenching device for knitting needles of circular knitting machines as claimed in claim 1, and being characterized in that:

the method comprises the following steps:

s1: placing a workpiece in a preheating chamber (31);

s2: removing oxygen in the preheating chamber (31);

s3: conveying the workpiece into a heating chamber (4), discharging gas in the heating chamber (4) into a preheating chamber (31), and then carrying out heating treatment;

s4: the workpiece is subjected to a cooling treatment in a cooling chamber (5).